Located just north of Crater Lake National Park, Diamond Lake has always seemed to be at the mercy of man.

The lake was first stocked with trout in the 1890s, and biologists soon found that they had a natural hatchery pond where 3-inch fingerlings grew in one season to a foot long.

In the good years, $25,000 in baby fish produced $2 million in spending by 100,000 fishermen, who took home 270,000 trout. Last year, only 5,000 fishermen showed up and caught 6,000 trout.

The lake's current chub infestation is not a new problem. The same thing happened in the 1940s. In 1954, ODFW poisoned the lake, and within five years, the plankton and insect life returned and Diamond Lake was trout heaven again.

But this time around there are a lot more things to consider, said Steve Denney, the Umpqua Watershed manager for the Oregon Department of Fish and Wildlife.

Poisoning the lake would create a huge amount of decaying fish, amounting to a stockpile of fertilizer flowing into the North Umpqua River, degrading the water quality for the salmon, steelhead and endangered searun cutthroat trout there.

ODFW has been experimenting with stocking the lake with Williamson River rainbow, which were born to eat tui chubs in Upper Klamath Lake on the other side of the Cascades, but that hasn't been effective.

The latest idea is to net the fish, which could be used to reduce the amount of fish before poisoning. It could also be used to knock back the numbers of chub to the point that big trout introduced into the lake would be able to control their numbers.

Commercial fisherman Bob Schones' crew went out on the lake this week to experiment with different techniques to see how effective they might be in removing the tui chub. He's also trying out a gillnet and a beach seine.

''It's not very often we get a chance to hear somebody say, 'Come catch all of them,''' said Schones, who is being paid $25,000 to try out the netting techniques.

Clad in the same orange raingear they wear netting herring in the salt waters of Yaquina Bay, they pulled in thousands of tui chub 3 to 5 inches long and loaded them into white plastic buckets for further examination and an eventual trip to a rendering plant.

Try as he might, Schones never could catch all 26 million tui chub in the lake, said Dave Loomis, an ODFW biologist.

''Seventeen million of them are this big, living back in the weeds,'' Loomis said, holding his thumb and forefinger a quarter inch apart. ''If you spent a lot of money and time, yes, you could remove a lot of fish, but you would leave alot. The bottom line is you could not eradicate the tui chub.''

Whatever the solution, Schones hopes netting fish is part of it. After 40 years on the ocean, he is eager for a change of scene.